Not sure if these (or the material I find in Santa Cruz) really match L. cyaneobasileucum – they don’t seem to have quite the cottony-coarse ornamentation on the stipe that Noordeloos refers to.

For those who don’t already know, both of these names refer to fungi originally described in Europe, but are assumed to be the correct names for our local specimens because these fungi occur in CA with imported (European) birch trees.